Biocidal plastic material

ABSTRACT

The invention provides a biocidal concentrate including zinc pyridinethione; and a second biocide selected to be biocidally effective in a pH range complimentary to zinc pyridinethione. The second biocide may be an aromatic halogenated phenol such as triclosan, dichlorophen and trichlorcarban. The invention also provides biocidal cleaning devices and plastic materials and methods of manufacture thereof.

TECHNICAL FIELD

[0001] This invention relates to a biocidal cleaning composition and theincorporation thereof into a biocidal cloth, sponge, paper, wounddressing, plastic or other substrate.

BACKGROUND ART

[0002] In domestic and hospital environments one of the most commonmethods of cleaning large surfaces is to wipe a cloth over suchsurfaces. Typically, the cloth will be moistened with water and mayadditionally have added a detergent or disinfectant. Cloths which do notcontain a disinfectant are ineffective in controlling the growth ofmicroorganisms. Indeed, the cloth itself may provide favourableconditions for the proliferation of such microorganisms and the actionof wiping such an infected cloth over a surface may produce an effectcounter to the desired outcome of making the surface more hygienic.Ordinary cleaning cloths which remain damp for a period are alsonotorious for the odours they develop, which are a result of microbialaction.

[0003] Soaking a cloth in disinfectant provides fairly short term reliefand requires the reapplication of the disinfectant to the cloth. Whilethis method uses only modest amounts of disinfectant, the quantity isnevertheless much more than is required to achieve adequate bactericidalaction. An extremely efficacious disinfectant is also required toprevent bacterial proliferation in the cleaning cloth itself, especiallyagainst the wide range of bacteria which are present in domestic andhospital situations. This somewhat unsophisticated method is alsowasteful in that every time the cloth is rinsed or washed thedisinfectant is removed and a new aliquot must be applied.

[0004] It has been practiced to incorporate an antimicrobial agen in anon-woven fabric as a colloidal suspension within an amorphous polymericbinder. The antimicrobial is not bound and is available to migrate tothe surface of the binding agent. Such systems require an internalreservoir having a very large quantity of antimicrobial agent—typically12 to 30 grams per square yard, and are more costly and less durablethan is desired.

[0005] Cellulose sponges containing zinc pyridinethione as an activeantibacterial agent are known. These sponges suffer from the drawbackthat a single wash in a washing machine is sufficient to remove much ofthe zinc pyridinethione. Thus, the sponge remains an effective weaponagainst bacteria for only a limited portion of its' working life, andmay lead to users having false confidence in its' potency.

[0006] The reason that the zinc pyridinethione is so readily removedunder normal washing conditions is that it is hydrolysed markedly ataround pH 11. Zinc pyridinethione is an effective biocide, but suffersfrom the drawback that its optimal range of efficacy is within the pHrange of 4.5 to 9.5. Many detergents and household cleaning agents havepH's above this range (for instance washing powders give rise tosolutions of around pH 11 and household bleaches have a pH of around13), and, as in use they are often present in greater quantities thanthe zinc pyridinethione, are capable of rendering it ineffective.

[0007] The use of high concentrations of zinc pyridinethione tocompensate for it's high loss under domestic cleaning conditions isundesirable as it has some human toxicity and is mildly irritating tothe skin, and severely so to the eye. Further, the zinc pyridinethionehas been shown to leach irreversibly out of the sponge over time.

[0008] There remains the problem then of providing a cleaning device,such as a cloth, sponge or similar, which will remain effective againsta wide range of bacteria for a significant period of time, yet will notbe unacceptably toxic.

[0009] Surprisingly, the inventor has found that one or more selectedbiocides, for example triclosan, dichlorophen (sometimes known as“dichlorophen” or DCP) or other chlorinated phenolic biocides, phenolicbiocides, or trichlorcarban, in combination with an organometallicbiocide, for example a metallic pyridinethione exhibit a synergy whichenables the combination to be effective against a wide range of bacteriaunder a wide range of pH conditions. Further, the addition of anacrylate binder, with or without other immobilising agents such as PVP,has also been found to render the biocidal mixture suitable forincorporation into a substrate for example a woven or non-woven cloth.

[0010] It is to be appreciated that such a biocide and method of bindingis not limited to textiles used for cleaning, but may also be applicableto other materials, such as sponges, paper, wound dressings, plastics oreven concrete.

DESCRIPTION OF THE INVENTION

[0011] It is to be understood that the use of the term “biocidal”throughout this specification is used in the sense that it refers tokilling one or more organisms, and thus it embraces both the terms“biocidal” and “biostatic” as commonly referred to in relation toreducing or maintaining the number of microorganism in a colony.

[0012] According to a first aspect the invention consists in a biocidalcomposition comprising a first biocide which is a metal pyridinethione;and a second biocide selected to be biocidally effective in a pH rangecomplementary to the metal pyridinethione, said second biocide selectedfrom the group consisting of halogenated phenols, phenols, derivativesof halogenated phenols, derivatives of phenols and trichlorcarban

[0013] Examples of derivatives include diphenyl ether derivatives,methylene bridged derivatives and the like. The most preferred compoundsare triclosan, dichlorophen and trichlorcarban. Examples of phenolicbiocides which may be used include, but are not limited to,ortho-phenylphenol, methyl parahydroxybenzoate, propylparahydroxybenzoate, ortho-cresol, meta-cresol and para-cresol.

[0014] Preferably the metal pyridinethione is zinc, sodium or magnesiumpyridinethione, and most preferably it is zinc pyridinethione.

[0015] According to a second aspect the invention consists in a biocidalcleaning device comprising a biocidal composition according to the firstaspect and a substrate.

[0016] According to a third aspect the invention consist a method ofmaking a biocidal cleaning device comprising the steps of combining abiocidal composition according to the firs aspect with a binding agentand contacting the resultant formulation with a substrate. Preferablythe method further includes the step of binding the composition to thesubstrate.

[0017] According to a fourth aspect, the invention consists in abiocidal plastic material comprising a biocidal composition according tothe fist aspect

[0018] According to a fifth aspect, the invention consists in a methodof making a biocidal plastic material according to the fourth aspectcomprising the steps of dissolving a biocidal composition according tothe first aspect in a plasticiser then compounding the plasticiser intoa polymer and forming the polymer into a desired shape.

[0019] Preferably in a biocidal cleaning device the metal pyridinethioneis present in amounts up to 2.5% of the Weight of the device. Morepreferably it is present in amounts of 0.05 to 1.0% of the weight of thedevice. Most preferably it is present in amounts of 0.1 to 1.0% of theWeight of the device.

[0020] Preferably in the biocidal cleaning device the second biocide ispresent in amounts up to 6% of the weight of the device. More preferablyit is present in amounts of 0.05 to 2.0% of the weight of the device.Most preferably it is present in amounts of 0.1 to 2.0% of the weight ofthe device.

[0021] Desirably the biocidal composition is prepared as a concentratewhich is diluted prior to impregnation into the substrate. In theconcentrate the metal pyridinethione is present in amounts up to 40%w/w. and more preferably 20 to 30% w/w.

[0022] Preferably the second biocide is present in the biocidalconcentrate in amounts up to 60% w/w, and more preferably 20 to 40% w/w.

[0023] The biocidal composition or concentrate may also include, in anycombination, a mineral oil. (PVP) polyvinylpyrrolidone, an alcoholicsolvent, an anionic surfactant, a non-ionic surfactant and water.

[0024] The substrate for use in the biocidal cleaning device ispreferably cloth.

[0025] Preferably the cloth weight is from 30 to 200 g/m², and morepreferably from 30-120 g/m² and the cloth is comprised of from: 70-100%rayon and 0-30% polyester. Preferably, the cloth also includes 0-30%polypropylene.

[0026] The substrate may also be sponge or a synthetic equivalent, paperor woven textile. In the case of a sponge, the weight can be up to 250g/m² or more.

[0027] When binding the biocidal mixture onto a substrate preferably thebinding means comprises a heat activated crosslinking reaction. The heatactivated crosslinking reaction may be carried out by a steam heateddrum or by infra red means. The crosslinking reaction may also beactivated by UV or visible light, electron beam or the like or chemicalinitiation.

[0028] The binding agent used in binding a biocidal mixture to asubstrate may be a polymer latex formulation or acrylate, in particularacrylate copolymers.

[0029] When making a biocidal plastic material the plasticiser isoptionally a hydrocarbon, preferably selected from the group comprisingpolybutene, low density polyethylene, low density polypropylene andparaffin wax. The plasticiser may also be, for example, an esterpreferably selected from the group comprising dibutyl phthalate.dioctylphthalate, or epoxidised vegetable oil or blends thereof.

[0030] Unless the context clearly requires otherwise, throughout thedescription and the claims, the words comprise, comprising, and the likeare to be construed in an inclusive sense as opposed to an exclusive orexhaustive sense that is to say, in the sense of including, but notlimited to.

BEST MODE FOR CARRYING OUT THE INVENTION

[0031] Preferred embodiments of the invention will now be described byway of example only. In the embodiments described zinc pyridinethione isused as the first biocide and triclosan as the second. However it willbe understood that the invention is not limited to this embodiment.

[0032] The combination of zinc pyridinethione and triclosan ordichlorophen provides important advantages over the use of eitherdisinfectant alone.

[0033] Zinc pyridinethione is effective at pH ranges from 4.5 to 9.5. Asmany detergents are strongly basic in nature, they can render zincpyridinethione ineffective at very high pH's. Triclosan, dichlorophen,trichlorcarban, chlorinated phenolic biocides and phenolic biocidesgenerally, on the other hand become more effective at higher pH ranges,in particular, at pH 9.5 and above.

[0034] In pH neutral or near neutral conditions, i.e. in the absence oflarge amounts of detergent, both the zinc pyridinethione and thecomplementary biocide work well. However, zinc pyridinethione, whileeffective against gram positive microorganisms, has been shown to beintrinsically only of limited effectiveness against gram negativebacteria, Triclosan and dichlorophen, for example, on the other handwhile having some gram negative activity are particularly effectiveagainst gram positive bacteria. In particular, the combination of thezinc pyridinethione and the complementary biocide as described above,has been shown to exhibit a marked synergistic effect in killingPseudomonas Aeruginosa.

[0035] The quantity of zinc pyridinethione used in the mixture toachieve a given bactericidal result is much less than if it was usedalone, with the added advantage that less of this relatively toxiccompound is used.

[0036] Thus, the combination of the two active ingredients is effectiveagainst a wide range of microorganisms at neutral pH's, and retains agood deal of this efficacy at higher pH's, in the presence ofdetergents.

[0037] The compositions of the present invention may also be usedagainst mould.

[0038] Toxicologically, DCP is much safer than Zinc pyridinethione.Toxicological data is shown in table 1. It is possible to formulate abiocidal mixture which has a high biocidal activity over a wide pHrange, against a broad spectrum of microorganisms yet exhibiting with alow level of toxicity to humans. TABLE I PROPERTY DICHLOROPHEN ZINCPYRIDINETHIONE Melting Point ° C. 175 240 Decomp. ° C. 290 240 pHStability >activity>pH decomposes pH>9.5 Oxidising Agents incompatibledecomposes Reducing Agents no effect decomposes Biodegradability Yes NoAcute Toxicity LD50 Oral  3300 mg/kg 160 mg/kg LD50 Dermal  5000 mg/kg100 mg/kg LD50 Subcut >3000 mg/kg 730 mg/kg LD50 IV   17 mg/kg  10 mg/kgTeratogenicity no effect reduced wt Fish Toxicity 23 mg/lt not availableIrritancy Slight dermal Moderate dermal Moderate eye Severe eyeGenotoxicity None None Regulatory: Max 0.1 mg/lt Max 0.1 mg/lt Pesticidein waste water in waste water Heavy Metal none Max 10 mg/lt

[0039] PVP (poly vinyl pyrrolidone) may be added optionally as acomplexing material. PVP modifies the solubility and dispersibility ofthe biocide in water, as disclosed in PCT/AU96/00224.

[0040] The ability of PVP to modify the solubility and dispersibilityhave been found extremely useful when incorporating composite biocidalmixtures of the present invention onto a substrate, for example, cloth.

[0041] It is postulated that the PVP and the second (non-zincpyridinethione) biocidal compound form a complex which providesexcellent binding between the cloth and the active ingredients,retaining the biocidal dispersion and providing a longer effective lifeto for the biocidal cloth. A postulated complex is shown in FIG. I. Itwill be appreciated that the dichlorophen need not be complexed with asingle polymeric strand of the PVP, but may cross-link one or more otherstrands. FIG. I. The structure of the complex formed betweenDichlorophen and PVP

[0042] Preferably for disinfecting and cleaning, polyvinylpyrrolidoneswith a degree of polymerisation (K value) of 15, 30, 60 and 90, mostpreferably 90 or copolymers with vinylacetate comprising from 20 to 80%polyvinylpyrrolidone (most preferably comprising at least 50%vinylacetate and can possibly possess cationic character) are used.

[0043] For impregnation, the amount of PVP polymer used is preferably inthe range of from 0.01 to 99.9 parts of the polymer for each part ofbiocide. More preferably the polymer is in the range of from 0.01 to 50parts and most preferably 0.01 to 10 parts for each part of phenolicbiocide.

[0044] The triclosan. DCP, trichlorocarban or other complementarybiocide can at any time be substituted by a PVP/DCP, PVP/triclosan,PVP/trichlorocarban of PVP/complementary biocide combination.

[0045] The addition of a binding agent such as an acrylate enhancesbinding of the biocide into a woven or non-woven textile. The additionof polyvinylpyrrolidone has also been found to increase the binding ofthe biocidal agents to the cloth, either alone or in combination withthe acrylate binder. More importantly, the addition ofpolyvinylpyrrolidone has been found to limit the biocide, so that as thesurface wears. fresh biocide is exposed at the fresh surface.

[0046] The biocidal mixture in any of its forms can be mixed intobinders such as acrylic or acrylic copolymer lattices or solutions. PVAlattices or PVA copolymer lattices or solutions, or any other polymerlatex or solution or blend of any of the previously described polymers.

[0047] The biocidal mixture, with or without PVP or binding agents canbe used for the treatment of any type of substrate, including woven ornon-woven textile, fabrics, sponges, scourers and the like, paper, orany other material. The treatments can be applied from solutions,suspensions or emulsions at ambient or other operational temperatures.

[0048] The inclusion of a mineral oil and an acrylate binder into theany of the above formulation can increase the suitability of thebiocidal mixture for cloth impregnation.

[0049] The most suitable fabrics for impregnation with the biocidalmixture are those which are rayon/polyester cloths which contain from 70to 100 percent rayon, although most known fabrics perform adequately. Inparticular, fabrics which weigh between 30 and 200 g/m² and especially30 and 120 g/m² have been found to be the most suitable.

[0050] Plasticisers are commonly added to synthetic polymers to modifytheir hardness and/or flexibility. Some common plasticisers arehydrocarbon polymers, such as polybutene, low density polyethylene, lowdensity polypropylene and paraffin wax. Other commonly used plasticisersare esters, such as dibutyl phthalate, dioctyl phthalate and similaresters, such as epoxidised vegetable oils or blends thereof and similaresters.

[0051] The biocide combination can be dissolved into a plasticiser orplasticisers and then compounded into a polymer which is then moulded byextrusion, injection moulding or some other process. The resulting itemwould then resist the growth of microorganisms on the surface of theitem by virtue of the incorporated biocides. If the plasticiser wereselected so as to be incompatible with the bulk material, it leaches outslowly, carrying effective amounts of the biocidal composition with itto the surface.

[0052] A use of particular interest is on materials used in evaporativecooling systems. Such systems typically harbour a wide range ofbacterial varieties, including legionella. The use of a boundbactericide in such systems would provide a low but long lasting levelof activity against bacteria. Such systems typically utilise a number ofplastic plates, and impregnating these with a biocidal mixture and abinder which was incompatible with the plastic, so as to leach slowly tothe surface, would provide a constantly self renewable biocidally activesurface.

EXAMPLES

[0053] Raw Material % W/W Example 1. Formulation of Biocidal ConcentrateThe following formulation is prepared: Zinc Pyridinethione 17.19Dichlorophen 34.39 Mineral Oil 22.92 PVP 8.44 Ethanol 3.44 Sodium LaurylEther Sulfate 0.70 Dioctyl Sulfosuccinate 1.50 Water qs 100% Example 2:Alternate Biocidal Concentrate Zinc pyridinethione 24.60 Dichlorophen24.60 Mineral Oil 16.40 PVP 7.20 Ethanol 2.40 Sodium Laurylether sulfate0.70 Dioctyl Sulfosuccinate 1.50 Water qs 100% Example 3. BinderFormulation Acrylic polymer self crosslinking 46.0 binder emulsion(approx 56% solids) Defoamer emulsion 0.15 (Foam Master. Henkel) Acryliccopolymer viscosity 3.60 controlling emulsion (Latekol DG. BASF) Sodiumdioctyl sulfosuccinate 1.0 Ammonium hydroxide (30%) 1.0 Ammonium nitrate1.0 Dyestuff dispersion to standard qs colour Water 47.25

[0054] The acrylic polymer binder emulsions is of a soft crosslinkingtype formulated with good tensile strength and rewetting properties foruse in non-woven applications.

Example 4 Application to Fabric

[0055] In this process, bales of textile fibre are fed into a machinefor making bonded, carded or hydroentangled non-woven fabric. Thesefibres can be of one type alone or of various combinations, for examplemost bonded, carded non wovens used for wipes are made from either rayonfibres or a combination of rayon and polyester fibres.

[0056] In the bonded, carded process the fibres are tangled together beone or more carding units in series, whereas the entangling takes placeusing high pressure water jets in hydroentangling. In both cases, at theend of the entangling stage the material is in continuous web form andis quite damp due to residual water which has been used in the course ofeach process.

[0057] The damp continuous web is then printed using a suitable dilutionof the concentrate of example 1 or 2 and the binder of example 3, whichis applied to isolated areas of the web. The damp, printed web passesthrough a heated zone to dry the printed fabric and cross-link thepolymeric binder. These heated zones are usually either composed ofsteam heated drums over which the fabric passes and dries by contact, orelse infra-red lamps which heat by radiation, or combinations of both.

[0058] This dry printed web is then rolled up for future slitting andcutting.

Example 5 Simulated Life Cycle of Cloth

[0059] The treated fabric is put into an automatic domestic clotheswashing machine set on a warm wash (35° C.). Five cycles of washing wereapplied which constitutes the simulated useful life of the fabric. Atthe end of five cycles of washing the fabric is put through thefollowing tests to validate that biocidal performance is still effectiveat the end of the working life of the fabric.

Example 6 Standard Sensory Tests

[0060] Standard sensory tests (stayfresh tests) were applied to thecloth to examine the resistance of the cloth to malodours produced bybacterial attack on food residues entrapped in the cloth in the normalcourse of kitchen use. Biocidal cloths produced according to theinvention gave good results when subjected to the following tests:

AS2609.1, AS2542.1.1, As2542.1.2 and AS2542.2.3

Example 7 Standard Quantitative Microbiological Test

[0061] A biocidal cloth according to the invention was subjected to astandard quantitative test for microorganisms. “Assessment ofAntibacterial Finishes on Textile Materials”: Test Method AATCC100-1993. This test is specifically designed for the assessment of thebiocidal properties of fabric treatments. These treatments are designedto kill microorganisms within the fabric, rather than on surfaces whichcome into contact with the fabric.

Example 8

[0062] Table II shows the effect of Pseudomonas Aeruginosa of fabricimpregnated with zinc pyridinethione (0.85%), a second fabricimpregnated with dichlorophen (0.85%) and a third fabric impregnatedwith a combination of dichlorophen (0.5%) and zinc pyridinethione(0.5%). The weights are given relative to the weight of dry fabric. Apositive sign indicates an increase in the bacterial population and anegative sign shows a decrease. TABLE II BIOCIDE DAY 1 DAY 2 zincpyridinethione +0.845 +0.35 dichlorophen +0.439 +2.12 dichlorophen/zincpyridinethione −0.94  −0.98

[0063] While the invention has been described herein with reference tozinc pyridinethione, those skilled in the art will appreciate that theuse of other metal pyridinethiones also form part of the same inventiveconcept.

The claims of the present invention are as follows:
 1. A biocidalconcentrate comprising: a first biocide which is a metal pyridinethione;and: a second biocide selected to be biocidally effective in a pH rangecomplementary to said metal pyridinethione, said second biocide selectedfrom the group consisting of: halogenated phenols, phenols, derivativesof halogenated phenols, derivatives of phenols, and trichlorcarbon.
 2. Abiocidal concentrate according to claim 1 wherein saidmetallo-pyridinethione is zinc pyridinethione.
 3. A biocidal concentrateaccording to claim 1 wherein said metallo-pyridinethione is sodiumpyridinethione.
 4. A biocidal concentrate according to claim 1 whereinsaid metallo-pyridinethione is magnesium pyridinethione.
 5. A biocidalconcentrate according to any one of claims 1 to 4 wherein the secondbiocide is dichlorophen.
 6. A biocidal concentrate according to any oneof claims 1 to 4 wherein the second biocide is triclosan.
 7. A biocidalconcentrate according to any one of the preceding clam wherein the metalpyridinethione comprises 5-25% w/w of the mixture.
 8. A biocidalconcentrate according to any one of the preceding claims wherein themetal pyridinethione comprises 11-16% w/w of the mixture.
 9. A biocidalconcentrate according to any one of the preceding claims wherein thesecond biocide comprises 32-37% of the mixture.
 10. A biocidalconcentrate according to any one of the preceding claims wherein thesecond biocide comprises 25-45% w/w of the mire.
 11. A biocidalconcentrate according to any one of the preceding claims furtherincluding a mineral oil.
 12. A biocidal concentrate according to any oneof the preceding claims further including polyvinlypyrrolidone.
 13. Abiocidal concentrate according to any one of the preceding claimsfurther including an alcoholic solvent.
 14. A biocidal concentrateaccording to any one of the preceding claims further including water.15. A biocidal clean device comprising: A biocidal concentrate accordingto any one of claims 1 to 14; and a substrate.
 16. A biocidal cleaningdevice according to claim 15 wherein the metal pyridine thione ispresent in an amount of to 2.5% of the weight of the device.
 17. Abiocidal cleaning device according to claim 15 or 16 wherein the metalpyridine thione is present in an amount of 0.05-10% of the weight of thedevice.
 18. A biocidal cleaning device according to any one of claims15-17 wherein the metal pyridine thione is present in an amount of0.1-1.0% of the weight of the device.
 19. A biocidal cleaning deviceaccording to any one of claims 15-18 wherein the second biocide ispresent in an amount up to 6% of the weight of the device.
 20. Abiocidal device according to any one of claims 15-19 wherein the secondbiocide is present in an amount of 0.05-2.0% of the weight of thedevice.
 21. A biocidal cleaning device according to any one of claims15-20 wherein the second biocide is present im an amount of 0.1-2.0% ofthe weight of the device.
 22. A biocidal cleaning device according toany one of claims 15-21 wherein the substrate is cloth.
 23. A biocidalcleaning device according to claim 22 wherein the cloth weight is from30-200 g/m².
 24. A biocidal cleaning device according to claim 22 or 23wherein the cloth weight is from 30-120 g/m².
 25. A biocidal cleaningdevice according to any one of claim 22-24 wherein the cloth iscomprised of from: 70-100% rayon; and 0-30% polyester.
 26. A biocidalcleaning device according to claim 25 comprising 0-30% polypropylene.27. A biocidal cleaning device according to any one of claims 15-21wherein the substrate is sponge or a synthetic equivalent.
 28. Abiocidal cleaning device according to any one of claims 15-21 whereinthe substrate is paper.
 29. A biocidal cleaning device according to anyone of claims 15-21 wherein the substrate is woven textile.
 30. A methodof making a biocidal cleaning device comprising the steps of: combininga biocidal concentrate according to any one of claims 1 to 14 with abinding agent; contacting the resultant formulation with a substrate;and binding the formulation to the substrate with binding means.
 31. Amethod according to claim 30 wherein said binding means is in the formof a heat treatment.
 32. A method of making a biocidal cleaning deviceaccording to claim 31 wherein the heat treatment is carried out by asteam heated drum.
 33. A method of making a biocidal cleaning deviceaccording to claim 31 wherein the heat treatment is applied by infra redmeans.
 34. A method according to claim 30 wherein said binding means isin the form of UV or visible light.
 35. A method of making a biocidalcleaning device according to any one of claims 30-34 wherein the bindingagent is a polymer latex formulation.
 36. A method of making a biocidalcleaning device according to any one of claims 30-34 wherein the bigagent is acrylate.
 37. A method of making a biocidal cleaning deviceaccording to any one of claims 30-36, wherein the substrate is selectedfrom the group comprising cloth, sponge or a synthetic equivalent, paperand woven textiles.
 38. A method of making a biocidal cleaning deviceaccording to any one of claims 30-37 wherein the absorbent material iscloth.
 39. Biocidal plastic material incorporating a biocidalconcentrate according to any one of claims 1-14.
 40. A method of makinga biocidal plastic material comprising the steps of: a) dissolving abiocidal mixture according to any one of claims 1-14 in a plasticiser;b) compounding the above formed biocide-plasticiser mixture into apolymer; and c) forming the plastic into the deed shape.
 41. A method ofmaking a biocidal plastic material according to claim 40 wherein theplasticiser is a hydrocarbon.
 42. A method of making a biocidal plasticmaterial according to claim 41 wherein the plasticiser is selected fromthe group comprising polybutene, low density polyethylene, low densitypolypropylene and paraffin wax.
 43. A method of making a biocidalplastic material according to claim 40 wherein the plasticiser is anester.
 44. A method of making a biocidal plastic material according toclaim 43 wherein the plasticiser is selected from the group comprisingdibutyl phthalate and dioctylphthalate.
 45. A method of making abiocidal plastic material according to claim 43 wherein the plasticiseris an epoxidised vegetable oil or a blend thereof.
 46. A biocidalconcentrate substantially as herein described with reference to any oneof the examples.
 47. A biocidal cleaning substantially herein describedwith reference to any one of the examples.
 48. A method of making abiocidal cleaning device substantially as herein described withreference to any one of the examples.
 49. A biocidal plastic materialsubstantially as herein described with reference to any one of theexamples.
 50. A method of making a biocidal plastic materialsubstantially as herein described with reference to any one of theexamples.